1. Field of the Invention
The present invention relates to a method of manufacturing a solid electrolytic capacitor having a solid electrolyte made of a conductive polymer.
2. Description of the Background Art
Recently, as electronic equipment is more digitalized and uses a higher frequency, and reflow temperature is increased by using lead-free soldering, there is a need for a capacitor having a smaller size, a larger capacity, a lower impedance in a high frequency region, and a high heat resistance.
The above need has been accomplished by a winding-type electrolytic capacitor in which a capacitor element formed by winding a cathode foil and an anode foil with a separator being interposed therebetween is accommodated in a metal case and sealed with a sealing rubber. In such an electrolytic capacitor, a conductive polymer having a high conductivity such as polypyrrole or polythiophene is used as a solid electrolyte.
Examples of solid electrolytic capacitors using a conductive polymer as a solid electrolyte include a solid electrolytic capacitor provided with polyethylenedioxythiophene as a solid electrolyte. The solid electrolyte of the solid electrolytic capacitor is produced by impregnating a capacitor element formed by winding an anode foil and a cathode foil with a separator being interposed therebetween with a solution containing 3,4-ethylenedioxythiophene and an oxidant solution in order, and causing a polymerization reaction (Japanese Patent Laying-Open No. 2005-109248).